4fi2 Notices respecting New Books. 



events, is well known, thoroughly appreciated, and frequently em- 

 ployed for analyzing the gases from regenerative furnaces in this 

 country. 



In this little work of 125 pages the author has succeeded in con- 

 densing so large an amount of information that any chemist, even 

 if previously entirely unaccustomed to the analysis of gaseous mix- 

 tures, may, with a moderate amount of practice, soon find himself 

 in a position to undertake the analysis of flue gases. 



One of the great advantages of the new method is that water is 

 made to supersede mercury in the various manipulations ; the 

 extent to which this substitution does away with the necessity for 

 personal skill in the operator can only be appreciated by those who 

 have had to analyze gases by the older processes. 



The author very properly commences by describing the apparatus 

 emploj r ed by him in sampling the gases to be examined, and the 

 directions given are so complete as to leave nothing to be desired ; 

 on the other hand, a properly educated chemist would never have 

 any difficulty in devising a method of withdrawing a portion of gas 

 from a flue or chamber, and storing it in a convenient vessel from 

 which small quantities could be removed as required. It must be 

 remembered, however, that the work is intended by the author for 

 the instruction of students and others who have not previously 

 acquired skill in gas-analysis. Among the devices described is 

 Bonny's automatic aspirator, which he has patented in Germany. 

 This instrument appears to us to have advantages which will make 

 it extremely useful under many circumstances. The chapter on 

 the measurement of gases will be found very useful, especially to 

 those who are unacquainted with the methods commonly employed 

 in scientific researches. The author (p. 30) states that " Gas- 

 meters are never altogether reliable ; but they give serviceable 

 approximate figures, especially if merely the number of revolutions 

 is noticed as shown by the dials, without looking for the absolute 

 volume of the gas passed." To this we may add that, although the 

 best gas-meters in this country are very well made, and quite suffi- 

 cient for every technical purpose unconnected with refined analysis, 

 it is very difficult to adjust even the most expensive ones to a less 

 error than one third of a per cent, on the total volume of the gas 

 passed. 



We think the author might with advantage have omitted the 

 description of his own gas-burette, as it is admitted to have been 

 superseded by newer and better forms. 



The descriptions of Honigmann's, Bunte's, and Orsat's apparatus 

 are given clearly ; and the same remark applies to the ingenious gas- 

 pipettes of Hempel, founded, we believe, on that of Doyere. 



Altogether this is a very valuable little work, and is absolutely 

 indispensable to every chemist who undertakes the technical analysis 

 of gases. The author is to be congratulated on the excellence of 

 the typography and the admirable manner in which the engravings 

 have been reproduced. Eor the fidelity of the translation the name 

 of Dr. Lunge is a sufficient guarantee. 



